Self reported cannabis use [ Time Frame: Evaluated each time subject seen over approximately 16 weeks ] [ Designated as safety issue: No ]

Subject quantifies and reports frequency of cannabis use prior to study participation and during

THC-COOH Quantification [ Time Frame: 12 times over approximately 16 weeks ] [ Designated as safety issue: No ]

Subjects provide urine samples to quantify levels of THC

Marijuana Craving Scale [ Time Frame: 15 times over approximately 16 weeks ] [ Designated as safety issue: No ]

Scale to assess severity of craving for marijuana

Relapse Rates [ Time Frame: After one week of abstinence ] [ Designated as safety issue: No ]

Subjects will frequently be evaluated to determine if they are able to maintain abstinence after one week of study treatment, at the end of the treatment period as well as at the end of the non-treatment follow up period.

Polysomnography [ Time Frame: Two nights prior to study treatment, three nights during study treatment and two nights at the end of study treatment (four weeks later) ] [ Designated as safety issue: No ]

Measurement of sleeping patterns

Cognitive Testing [ Time Frame: Once pre-treatment, twice during treatment (within 4 weeks) and once during the non-treatment follow up (within 8 weeks) ] [ Designated as safety issue: No ]

Various computerized tests of memory, attention and learning

Original Secondary Outcome Measures ICMJE

Same as current

Current Other Outcome Measures ICMJE

Not Provided

Original Other Outcome Measures ICMJE

Not Provided

Descriptive Information

Brief Title ICMJE

Safety and Efficacy of a FAAH-Inhibitor to Treat Cannabis Withdrawal

Official Title ICMJE

FAAH-Inhibitor for Cannabis Dependence

Brief Summary

Cannabis dependence is associated with changes in the brain's cannabinoid system. When cannabis dependent individuals try to quit using cannabis, some of them experience problems that make it difficult for them to achieve and maintain abstinence. Therefore, reducing the problems related to quitting cannabis may facilitate abstinence. One way to do this is by harnessing the brain's capacity to make its own cannabis-like substances - endocannabinoids. One of the main endocannabinoids is anandamide. The study is based on the hypothesis that the problems related to quitting cannabis use will be reduced by increasing the brain levels of anandamide. Furthermore, by reducing the problems related to quitting cannabis, people will be less likely to relapse. Brain anandamide levels will be increased by blocking the breakdown of anandamide using a fatty acid amide hydrolase inhibitor (FAAH-I). The effects of a novel FAAH-I cannabis withdrawal and relapse in cannabis dependent subjects will be studied in a double-blind, randomized, controlled, proof-of-concept study. Cannabis-dependent subjects will receive placebo or the FAAH-inhibitor PF-04457845 in a 2:1 randomization. The trial consists of a 1 week inpatient stay to achieve abstinence, a 3 week outpatient treatment phase and a 8 week follow-up phase. Abstinence and relapse will be measured at various times during this 12 week study.